Conventionally, selective separation and recovery of a predetermined component from a solution to be treated where various components exist together are performed in fields of a resource recovery, a wastewater treatment, an analytical chemistry, or the like. As methods separating and recovering the component dissolved in the solution to be treated, various methods such as a cation exchange resin method, an inorganic ion adsorption method, an electrolytic method are used in accordance with characteristics of a substance to be a separation object. Among them, a recovery method by using an inorganic ion exchanger using zeolite as an exchanger is considered as a practical method from a point of view of a cost for recovery.
In the recovery method using the inorganic ion exchanger, recovery efficiency is affected by the characteristics of the substance to be the recovery object. Therefore, it is an actual circumstances in which an adsorption substance is examined by each substance to enable the effective recovery. Accordingly, research and development to select an appropriate method are performed in each field as for the recovery methods and the adsorption substances. In particular, high-level radioactive substances such as a cesium (Cs) ion, a strontium (Sr) ion, an iodine (I) ion, and lithium (Li) ion are contained in wastewater discharged from a nuclear power plant. In consideration of influences on environment and human bodies, an expectation for an adsorption substance having higher recovery efficiency has risen.
In a conventionally used adsorbent to recover metal cations, a substance to be adsorbed is limited according to characteristics thereof. Recoveries of various substances are required aiming for an antipollution measure, a recovery for industry, and so on. Therefore, an expectation for an adsorbent capable of recovering substances which are conventionally difficult for recovery and whose recovery efficiency is bad, with high efficiency rises.